A Reason for Everything: Natural Selection and the English
ImaginationBy Marek Kohn
London: Faber and Faber.

A Reason for Everything is a popular history of British
evolutionists from the mid nineteenth to the end of the twentieth centuries. It
is well-written and researched throughout. The author, Marek Kohn, read biology
at Sussex University, and is the author of numerous other works on drug culture,
evolution, biology and society. Six evolutionists are discussed in increasing
biographical detail: Alfred Russel Wallace, Ronald Fisher, J. B. S. Haldane,
John Maynard Smith, William Hamilton and Richard Dawkins. The series of
biographical sketches grows more in depth and contains some new material when we
reach Maynard Smith, Hamilton and Dawkins because Kohn makes use of interviews
and correspondence with family, colleagues and the subjects themselves.

It would have been nice had Kohn included a sketch of Charles
Darwin, especially since it was Darwin who first discovered the significance of
and coined the terms 'natural selection' and 'adaptation', terms which Kohn's
book particularly targets. However Kohn considered that Darwin's case is so
well-known and abundantly available that he would focus on others. It is hard to
disagree with him.

The first evolutionist to be discussed, therefore, is Wallace
who is usually remembered as the 'co-discoverer' of evolution by natural
selection. This is a distinction both deserved and undeserved. While Wallace did
independently propose that varieties of organisms will diverge from an ancestral
stock to the point of speciation by differential survival of well-suited forms,
it is perhaps an unfortunate short-hand to say that he and Darwin discovered
'the same' theory. By assuming a singular entity 'the theory' we shrink what
actually happened historically to an unwarranted simplicity. It is also somewhat
misleading to then attach the name Darwin coined for his ideas to the thought of
both men. As is often remarked, there were many differences between them.
Wallace never appreciated Darwin's insight that a farmer or breeder's selection
of particular individuals, because of desirable characteristics or stock to
breed from is directly parallel to certain characteristics of organisms in
nature making the difference between their surviving to reproduce or not. Hence
Darwin called the effect 'natural selection' because it was akin to a breeder's
selection. Wallace much preferred Herbert Spencer's term 'the survival of the
fittest'. In fact Wallace even crossed out the words 'natural selection' in his
copy of The Origin of Species (1859) and wrote in 'survival of the
fittest' in the margins. As is well known, the implementation of this less
suitable and more tendentious term has unleashed cascades of misunderstandings
and inspired or was used in many forms of elitist weak-to-the-wall thinking.
Similarly, it is misleading to say that Herbert Spencer thought up 'natural
selection' before Darwin. (81) Spencer had a similar idea but using the
identical label renders the statement misleading.

Kohn's treatment of Wallace is sympathetic and one wishes it
were not so brief. Kohn speculates that Darwin and Wallace hit on such similar
theories of evolution because of similar early interests such as collecting
beetles and all the attention to detail and diversity that this entailed. This
is quite a general and inadequate explanation. Thousands upon thousands of their
contemporaries collected beetles and yet only two came to explain the diversity
of life in what we now call evolution by natural selection. If a general
explanation is sought, one should point rather at their extensive periods of
collection, ability to observe geographical distribution around the world first
hand and penchant for generalization.

Kohn also makes a few minor mistakes as when he asserts that
Charles Lyell and J. D. Hooker arranged a special meeting of the Linnaean
Society for the reading of the joint paper by Darwin and Wallace announcing
their views in 1858.(33) (See Desmond and Moore, Darwin, 1989, 469)
Similarly, when discussing Wallace's many fringe interests, Kohn claims that
they were confined to the supernatural. This is clearly the case with
spiritualism or the unsupported assertion that human beings must have had some
supernatural help in their evolution but not the case with phrenology,
mesmerism, anti-vaccination and radical land reform. Wallace clearly had wide
interests, strong convictions and an inability to give up a view once he had
become convinced it was true, no matter how much contrary evidence he later
encountered.

The treatment of the five subsequent evolutionists is
thorough, intimate and thoroughly enjoyable. Kohn combines a discussion of their
lives and personalities as well as their work and their scientific contexts.
After reading Kohn's chapters one feels one almost knows Hamilton or Fisher.
Nevertheless the book does assume some prior knowledge of some of the scientific
issues such as the debates over selectionism.

Only in some of Kohn's general remarks and in his overall
argument is the book less convincing. For example, Kohn repeats what has become
almost a commonplace statement in textbooks “Darwinism was widely assumed to
have been consigned to the dustbin of the nineteenth century”. (85) Yet this
is not the case. It is true that many writers believed that Darwin's mechanism
of natural selection could not be the main explanation, but he was universally
regarded as the greatest biological thinker and theorist for having convincingly
demonstrated how all the vast variety of living forms on earth originated,
common descent. In countless books and articles from the turn of the century and
in the following decades Darwin was still praised in terms as high as one finds
in the many obituaries and biographical notices that appeared in 1882-3 just
after Darwin's death. I suspect that the disrepute or inadequacy of Darwinism
has come to be somewhat exaggerated since a second triumph-story has come to be
told. How can the new synthesis be proclaimed as coming to the rescue in the
history of science if it were only filling in some of the vague sub clauses in
Darwin's theory?

There is a similar change in the story since genetic
mutations have become such an important component of biology. Now one constantly
reads in popular accounts that mutations are the only source of variation. Yet
Darwin's great theory included variation, selection and heredity. What was
variation for Darwin if genetic mutations were not yet known? Darwin referred to
the fact that all individual organisms are unique and it was these tiny
variations between one another that could make the difference between survival
and reproduction and ceasing to exist. So the modern role of genetic mutations
in the story of Darwin and evolution has overshadowed the far greater source of
genetic variation for many species, sexual reproduction.

But the real argument of Kohn's book, if sometimes out of
sight, is that an emphasis on adaptation is particularly British and that this
emphasis can be explained by some other characteristics of British thinkers.
And, as Kohn puts it, “An adaptationist will tend to assume a reason for
everything.” (13) Hence the title of the book. John Maynard Smith agreed “I
never knew a birdwatcher who was not a naive adaptationist”. (6) A few broad
brush explanations are offered for British adaptationism. For example, there is
the British tradition of natural history from Gilbert White onwards. But these
sorts of explanation are little more than a rhetorical characterization. There
is no measurement or even comparison with other countries. The assertion that
'adaptationists' are primarily British is not based on any quantification of
publications or other data. Hence it could be contradicted by other plausible
sounding characterizations.

Even so an explanation such as 'it is something about
Englishmen' or 'something in their context or culture', is unnecessary.
Selectionist or adaptationist thinking was proposed by two Englishmen, Darwin
and Wallace, and the first converts were also therefore British. We need not be
surprised that a tradition founded and passed on by individual conversation and
instruction in a country diffuses and continues. (Rogers, 1995) The doctrines
were spread to America, in contrast, largely by print. This gives more leeway
for interpretation and divergence from the thought of innovators like Darwin and
Wallace. And this is precisely what we observe.

In my opinion the biographical histories are stronger than
the theme or argument of the book. Yet one can always quibble about a book that
covers so much time and material because there is so much food for thought. This
should not be allowed to subtract from the merit of a delightful book which it
is to be hoped will be widely read.